|MadSci Network: Zoology|
Dear Cerulean, Your squirrels in the Arctic are ground squirrels . They have a completely different lifestyle underground, as opposed to the arboreal squirrels we know. The ecology of arboreal squirrels depends on the individual species but basically the competition is fierce. They may even be killed and eaten by their own species, although inter-specific competition is suspected in American grey populations in Europe and the native red squirrel. (This is a whole different ball-game, where battle has raged for generations between the grey squirrel virus faction and the more physical competitive ideas of competition). However, Iím afraid your answer needs no species details unless you would like to compare the Eastern and western American grey squirrels(and a red) or the Canadian ground squirrels or gophers with their Asian brothers (same species, known as sousliks). In all events, the gopher lives below -30o (down to -40oC) and is the best known mammal to super-cool or allow its body to lower its temperature below freezing! Hibernation among mammals is common, but this is really special as ice canít be allowed to form in the fluid bloodstream. Basically the tundra habitat demands the ground squirrel chooses a deep sandy burrow where it can spend most of the year sheltered from extreme temperatures. This has helped it to evolve the extreme features it needs for survival. If you want to compare arboreal squirrels, their ďdreyĒ is usually formed in the branch of a tree in Summer and within a hollow of a tree in winter. Temperatures in forests never sink as low(or rise as high) as exposed ground, as youíll soon find if you notice cold exposed hillsides in Winter or cool woods in mid-Summer. They may die if their stores of food run out or maybe they just got old---. Good luck with your mammal studies in future. Hopefully we can help you more with questions for which we can define your answer more closely or advise you on local fauna that you can really enjoy observing. As far as these cold wildernesses are concerned, you could be grateful that you donít have to survive for ten months of the year , asleep in an igloo!
Try the links in the MadSci Library for more information on Zoology.